Optical pulse phase extraction recovery system

Abstract

The application relates to a light pulse phase extraction recovery system suitable for the field of laser spectrum and optical measurement. The light pulse phase extraction recovery system comprises a to-be-measured light pulse (1), a first 1*2 optical coupler (121), a second 1*2 optical coupler (122), a first optical spectrum analyzer (21), a second optical spectrum analyzer (22), a first square operator (41), a second square operator (42), a first dispersive optical fiber (31), a second dispersive optical fiber (32), an optical phase modulator (4), a waveform generator (5), an electrical frequency spectrum analyzer (6), a difference operator (7), a convolution operator (8), a division operator (9) and an integral operator (10).

Description

Technical Field

[0001] This invention relates to the fields of laser spectroscopy and optical measurement, and in particular to a spectral phase extraction and recovery system. Background Technology

[0002] The optical field distribution of a light pulse can be described in both the time and frequency domains. For frequency domain spectral measurements, current spectrometers can only provide the amplitude spectrum, losing the phase information. Since the phase contains important information about the optical field distribution, even if the measured amplitude spectrum is the same, different phases will result in significant differences in the corresponding true optical field. Therefore, to fully represent all the information of the true optical field, both spectral amplitude and phase must be measured simultaneously. Traditionally, frequency-resolved optical switching (FROG) or spectral phase interferometry are used to detect the optical phase. However, FROG requires the generation of second harmonics in a nonlinear crystal and is generally only suitable for phase detection of high-energy ultrashort light pulses; while spectral phase interferometry requires good monochromatic coherence of the light field being detected, and the accuracy of optical phase detection is highly sensitive to environmental factors such as temperature and vibration of the detection system. Summary of the Invention

[0003] The technical problem to be solved by this invention is to overcome the shortcomings of existing optical pulse phase detection methods and to propose a method for directly extracting and recovering optical phase information by measuring the optical amplitude spectrum using a commonly used spectral analyzer.

[0004] The technical solution of the present invention:

[0005] An optical pulse phase extraction and recovery system includes: an optical pulse to be measured, first and second 1×2 optical couplers, first and second spectrometers, first and second exponentiation units, first and second dispersive optical fibers, an optical phase modulator, a waveform generator, an electrical spectrum analyzer, a difference unit, a convolution unit, a division unit, and an integration unit.

[0006] The connections of the various devices are as follows:

[0007] The optical pulse to be tested is connected to the input port of a first 1×2 optical coupler. The first output port of the first 1×2 optical coupler is connected to the input port of a first spectrometer. The output of the first spectrometer is connected to the input port of a second 1×2 optical coupler via a first exponentiation unit. The first port of the second 1×2 optical coupler is connected to the first input port of a difference unit. The second port of the second 1×2 optical coupler is connected to the divisor port of a division unit. The second output port of the first 1×2 optical coupler is connected to the optical input port of an optical phase modulator via a first dispersive fiber. The optical output port of the optical phase modulator is connected to the second spectrometer via a second dispersive fiber. The input port of the second spectrometer is connected to the second input port of the differential operator via the second exponentiation unit. The output port of the differential operator is connected to the first input port of the convolution operator. The electrical input port of the optical phase modulator is connected to the first output port of the waveform generator. The second output port of the waveform generator is connected to the input port of the electrical spectrum analyzer. The output port of the electrical spectrum analyzer is connected to the second input port of the convolution operator. The output port of the convolution operator is connected to the dividend port of the divider operator. The output port of the divider operator is connected to the input port of the integrator operator. The output port of the integrator operator can then extract and recover the phase information of the light pulse under test.

[0008] The first output port of the waveform generator 5 outputs a sine signal, and the second output port of the waveform generator 5 outputs a step signal;

[0009] The optical phase modulator 4 is modulated near zero of the sinusoidal signal at the first output port of the waveform generator 5;

[0010] The first port of the second 1×2 optical coupler 122 contains the squared amplitude spectrum of the optical pulse |F(ω)|. 2 The output port of the second exponentiation unit 42 is the amplitude squared spectrum |F| obtained after phase modulation of the light pulse. φ (ω)| 2 The first input port of the convolutional operator 8 is a differential signal spectrum. The second input port of convolution operator 8 contains the amplitude spectrum of the step signal: H(ω), and the output port of convolution operator 8 yields: The output port of the divider 9 obtains the phase differential delay information of the optical pulse under test, denoted as: The phase information of the optical pulse under test is extracted and recovered from the output port of the integrator 10. Attached Figure Description

[0011] Figure 1 Optical pulse phase extraction and recovery system. Detailed Implementation

[0012] The present invention will now be further described with reference to the accompanying drawings.

[0013] like Figure 1 The optical pulse phase extraction and recovery system includes: a light pulse to be measured 1; first and second 1×2 optical couplers 121 and 122; first and second spectrometers 21 and 22; first and second exponentiation units 41 and 42; first and second dispersive optical fibers 31 and 32; optical phase modulator 4; waveform generator 5; electrical spectrum analyzer 6; differential unit 7; convolution unit 8; division unit 9; and integral unit 10.

[0014] The connections of the various devices are as follows:

[0015] The optical pulse to be tested 1 is connected to the input port of the first 1×2 optical coupler 121. The first output port of the first 1×2 optical coupler 121 is connected to the input port of the first spectrometer 21. The output of the first spectrometer 21 is connected to the input port of the second 1×2 optical coupler 122 via the first exponentiation unit 41. The first port of the second 1×2 optical coupler 122 is connected to the first input port of the difference unit 7. The second port of the second 1×2 optical coupler 122 is connected to the divisor port of the division unit 9. The second output port of the first 1×2 optical coupler 121 is connected to the optical input port of the optical phase modulator 4 via the first dispersive fiber 31. The optical output port of the optical phase modulator 4 is connected to the second dispersive fiber 32 via the second dispersive fiber 32. The input port of the second spectrometer 22 and the output of the second spectrometer 22 are connected to the second input port of the difference operator 7 via the second exponentiation operator 42. The output port of the difference operator 7 is connected to the first input port of the convolution operator 8. The electrical input port of the optical phase modulator 4 is connected to the first output port of the waveform generator 5. The second output port of the waveform generator 5 is connected to the input port of the electrical spectrum analyzer 6. The output port of the electrical spectrum analyzer 6 is connected to the second input port of the convolution operator 8. The output port of the convolution operator 8 is connected to the dividend port of the divider operator 9. The output port of the divider operator 9 is connected to the input port of the integrator operator 10. The output port of the integrator operator 10 can extract and recover the phase information of the light pulse to be measured.

[0016] The first output port of the waveform generator 5 outputs a sine signal, and the second output port of the waveform generator 5 outputs a step signal;

[0017] The optical phase modulator 4 is modulated near zero of the sinusoidal signal at the first output port of the waveform generator 5;

[0018] The dispersion of the first dispersive fiber 31 and the dispersion of the second dispersive fiber 32 are opposites of each other.

[0019] The first port of the second 1×2 optical coupler 122 contains the squared amplitude spectrum of the optical pulse |F(ω)|.2 The output port of the second exponentiation unit 42 is the amplitude squared spectrum |F| obtained after phase modulation of the light pulse. φ (ω)| 2 The first input port of the convolutional operator 8 is a differential signal spectrum. The second input port of convolution operator 8 contains the amplitude spectrum of the step signal: H(ω), and the output port of convolution operator 8 yields: The output port of the divider 9 obtains the phase differential delay information of the optical pulse under test, denoted as: The phase information of the optical pulse under test is extracted and recovered from the output port of the integrator 10.

Claims

1. A system for extracting and restoring the phase of an optical pulse, characterized in that, The system includes: the light pulse to be tested (1), the first and second 1×2 optical couplers (121) and (122), the first and second spectrometers (21) and (22), the first and second exponentiation units (41) and (42), the first and second dispersive optical fibers (31) and (32), the optical phase modulator (4), the waveform generator (5), the electrical spectrum analyzer (6), the difference unit (7), the convolution unit (8), the division unit (9), and the integration unit (10). The connections for each component are as follows: The light pulse to be tested (1) is connected to the input port of the first 1×2 optical coupler (121). The first output port of the first 1×2 optical coupler (121) is connected to the input port of the first spectrometer (21). The output of the first spectrometer (21) is connected to the input port of the second 1×2 optical coupler (122) via the first exponentiation unit (41). The first port of the second 1×2 optical coupler (122) is connected to the first input port of the difference unit (7). The second port of the second 1×2 optical coupler (122) is connected to the divisor port of the division unit (9). The second output port of the first 1×2 optical coupler (121) is connected to the optical input port of the optical phase modulator (4) via the first dispersive fiber (31). The optical output port of the optical phase modulator (4) is connected to the second spectrometer via the second dispersive fiber (32). The input port of the analyzer (22) is connected to the second input port of the differential operator (7) via the second exponentiation operator (42), and the output port of the differential operator (7) is connected to the first input port of the convolution operator (8); the electrical input port of the optical phase modulator (4) is connected to the first output port of the waveform generator (5), the second output port of the waveform generator (5) is connected to the input port of the electrical spectrum analyzer (6), the output port of the electrical spectrum analyzer (6) is connected to the second input port of the convolution operator (8), the output port of the convolution operator (8) is connected to the dividend port of the divider operator (9), the output port of the divider operator (9) is connected to the input port of the integrator operator (10), and the output port of the integrator operator (10) extracts and recovers the phase information of the light pulse to be measured. The first output port of the waveform generator (5) outputs a sine signal, and the second output port of the waveform generator (5) outputs a step signal; The first port of the second 1×2 optical coupler (122) contains the squared amplitude spectrum of the light pulse to be measured. The output port of the second exponentiation unit (42) is the squared amplitude spectrum of the light pulse under test after phase modulation. The first input port of the convolution operator (8) contains the differential signal spectrum: The second input port of the convolution operator (8) contains the amplitude spectrum of the step signal. The output port of the convolution operator (8) is the convolution spectrum obtained by convolving the difference signal spectrum with the step signal amplitude spectrum: The phase differential delay information of the optical pulse under test is obtained at the output port of the division unit (9). The integrator (10) performs integration on the phase differential delay information of the optical pulse under test, and extracts and recovers the phase information of the optical pulse under test from the output port of the integrator (10). .

2. The optical pulse phase extraction and recovery system according to claim 1, characterized in that: The optical phase modulator (4) is modulated near zero of the sinusoidal signal at the first output port of the waveform generator (5).

3. The optical pulse phase extraction and recovery system according to claim 1, characterized in that: The dispersion of the first dispersive fiber (31) and the dispersion of the second dispersive fiber (32) are opposites of each other.

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